Department of Orthopaedic Surgery, Weihai Municipal Hospital, China.
Orthop Surg. 2011 May;3(2):113-8. doi: 10.1111/j.1757-7861.2011.00132.x.
Anterior cervical discectomy is commonly used to treat radiculopathy and myelopathy. Although the size of the implanted graft may influence the clinical outcome of anterior reconstruction of the cervical spine, the ideal graft height remains arguable. The objective of the current study was to study the interrelations of graft height and immediate biomechanical stability in an anterior cervical discectomy model.
Six fresh-frozen human cadaver cervical spines (C1-T1) were tested in five sequential states. The first state tested was the "normal" state (specimens with intact discs). The other four states were tested after C5-C6 discectomy by the Smith-Robinson graft technique, using graft thicknesses of 100%, 120%, 140%, and 160% of the baseline height. The baseline height was defined as the intervertebral disc height of C5-C6 at the intact stage. Intervertebral segment flexion, extension, bending and rotation of C5-C6 were recorded using a 3D laser scanner and analyzed using Geomagic Studio 5.0 software.
Bone grafting at 100% baseline height after discectomy provided the least stability and the greatest movement range. With increasing height of grafts, the movement range of the cervical spine declined. Immediate stability of the operated segments was significantly increased by grafting with 140% and 160% baseline heights compared to the baseline height condition.
Strut-graft with appropriate distraction after Smith-Robinson anterior cervical discectomy plays an important role in the whole immediate biomechanical stability of the lower cervical spine. A graft height of 40% greater than baseline may be ideal after single discectomy in clinical practice.
颈椎前路椎间盘切除术常用于治疗神经根病和脊髓病。虽然植入移植物的大小可能会影响颈椎前路重建的临床结果，但理想的移植物高度仍存在争议。本研究的目的是研究颈椎前路椎间盘切除模型中移植物高度与即刻生物力学稳定性的相互关系。
对 6 具新鲜冷冻人颈椎（C1-T1）尸体标本进行了 5 个连续状态的测试。第一个测试状态为“正常”状态（椎间盘完整的标本）。其余 4 个状态是在 C5-C6 椎间盘切除后，采用 Smith-Robinson 移植物技术进行测试，移植物厚度分别为基线高度的 100%、120%、140%和 160%。基线高度定义为完整阶段 C5-C6 的椎间盘高度。使用 3D 激光扫描仪记录 C5-C6 的椎间节屈伸、弯曲和旋转，并使用 Geomagic Studio 5.0 软件进行分析。
椎间盘切除术后用 100%基线高度的骨移植物提供的稳定性最低，活动范围最大。随着移植物高度的增加，颈椎的活动范围减小。与基线高度条件相比，用 140%和 160%基线高度的移植物进行植骨可显著增加手术节段的即刻稳定性。
Smith-Robinson 颈椎前路椎间盘切除术后适当撑开的支柱移植物对下颈椎即刻整体生物力学稳定性起着重要作用。在临床实践中，单次椎间盘切除术后，移植物高度比基线增加 40%可能是理想的。
